Purification of oil



July 25, 1933- w. G. HOFFMAN ET AL 1,919,655

I PURIFICATION OF OIL Filed July 12, 192.9 5 sheets-sheet' 1 HEA TER EINVENTORS,

July 25, 1933- w. G, HOFFMAN Er AL 1,919,655

PURIFIGATION OF OIL Filed July 12, 1929 3 sheets-sheet 3 nl ,4i/R BLOWERl l @maza .MW

Patented July 25, 1933 WALTER e. HOFFMAN, or MouNr LEBANON,PENNSYLVANIA, essreNons, BY MnsNn ENT ori-1ers l AND JAMns n. MILLER,YorA PITTSBURGH; assreNMnNTs ro BocJL CORPORATION, fi

F PITTSBURGH, PENNSYLVANIA, A CORPORATION 0F DELAWARE Y 'l PURIFIGATLONor orL Application led July 12,

rlhis invention relates generally to the` I purification of oil *andmcreparticularly to Y a process for treating used oils in order to` removetherefrom impurities such as water,

gasoline, solid carbon paticles and other iin-- purities,fand toneutralize acid constituents thereof. 'l 1 I `In accordance with ourlinvention we introduce into a tank a mixture'of oil., anal-` kali, andpreferably diatomaeeous earth, and'blow air through the mixture in orderto agitate it. The mixture -is'heated to the desired temperature inorder to expel the Waterl and lighter hydrocarbons, such as gasoline,and to aid in the reaction of the alkali with the acid constitueiits ofthe oil...

Thereafter the mixture is passed vfrom the heating tank to a filterwhich removes the diatomaceous earth and anyfsolid particles of carbonor other material which have been deposited inthe oil. Y 1 In theaccompanying drawings, which il lustrates the present' preferredembodiment of our invention,`

AFigure 1 `is avertieal section, parts being shown in elevation,the'section being taken' on the lineI-I ofv Figurev 2'.

Figure 2 isV a yhorizontal section on the line H-II ofFigure 1,- y

Figure 3 isa horizontal'seetion' on line IlI---HII of Figure 1, and pFigure 4 is a vertical section on-theline IV-IV `of Figure 2.x-

liteferringV to thel accompanying the . drawings, there is shownaheating tank '2 comprising anouter casing and an innercasing4 of sheetmetal. The casing is lined withan insulating material 5 such as mineralwool..v The tank 'is provided with acoverG also comprising anouter-casing 7, an inner cas# ing 8 and insulation 9. The bottom of theVtank 2 is similar in construction to the cover 6 and likewise comprisesouter and inner casings 10 and l1, respectively, the spacek terial 12,such as mineral wool.. i v

A heating-'001115 1s arranged vbetween the betweenwhich is' filled withinsulating mainner and' outer easings 3 and `4 and is connected to asuitable source` of current through the leads 16. Connected 1n seriesvthe bottom of the tank.

i through .a pipeV 40.

the inlet 448 of a filter 1929. sei-m1 No, 377,763.

,afterv the desired temperature inthe tankhas been reached. .Y The cover6 of the tank has a pipe20`. eX- tending therethrough, the outer end ofthe pipe being normally closed by a cap 21. The pipe is Vfor the purposeof enabling al thermometer or other instrument to be inserted into thetank in order to check up on the temperature of the 'oil' being treated.y A. vent pipe 22 shown in Figure 4 extends, through the rear wall ofthe tank 2. 1 Anair blower 30 andan oil pump glare mounted on a shelf 32supported between framework 33, which yalso supports the The air.blower` is driven heating tank 2.

by a motor 34 and the oilpump by a motor 35. The air blower has a pipe36 connected at oneV end to the blower and having its oppositeendextending upwardly into the tank and then downwardly ina U-shape, sothat the delivery lend'? of the pipe lies adjacent 'lhe mixture of oiland` chemicals is supplied to the tank 4The pipe 40 leads'to the inlet41 ofjthe'oil pump `31, and ktheout` let 42v of thepump isconnected to apipe 43 which extends upwardly intofthe tank." Y, The inlet'41andt'heoutlet 42 ofthe oil'. pump are provided with tln'ee-way valves.l 44 and45, respectively. The outlet vof 'the valve 45 is connected by pipes 46and47 to 49. p A heating tank outlet `pipe has itsl upper end in com-90l munication withlthe tank and` its lower end' 51` in communicationwith the three-way' valve 44 arranged in the inlet to the `*oil pump Apipe 55 is connected at its upper end to the pipe 46 and at its lowerend to a'pipe'56 which leads tothe three-wayf v ranged in the tank.

at 37 adjacent the bottom' of the tank.

oil to pass through the pipes 55 and 56 to the inlet of the oil pump 31,rather than forcing the oil through the lifter 49 against this excesspressure. f

The filter 49 is of the press type commonly used in filtering solidsfrom liquids, and comprises a series of alternately arranged plates 60vand frames 61 having lilter paper, not shown, arranged therebetween. Thepress has a movable end plate G2 which may be forced inwardly to forcethe plates, frames and filters closely together. arrangement shown, theend plate 62 is carried by a screw G3 having an enlarged head G4provided with openings G5, in which a bar may be inserted to turn thehead and screw. ylfhe screw (38 is mounted in a frame 66 so that uponrotation of the head (34 the end plate 62 compresses the piates G0 andframes G1.

The current for the heating coil l5 is controlled .by a switch 70, shownin Figure 1, ,and the motors 34 and 35 are controlled from panels 71 and72, respectiveiy.

In purifying oil according to our process, we mix the oil with an alkalisuch as sodium carbonate, in the proportion of about 1 lb. of sodiumcarbonate to gals. of oii. This mixture is introduced through the pipeand is pumped by the pump 31 through the valve and pipe 43 into the tank2. rlhe oil is pumped into the tank until it begins to flow from thedrain cock 8O connected by a pipe 81 to the overflow-pipe 82, ar-

The supply of oil into the tank through the pipe 43 is then stopped andthe motor 34 is started, which causes air Vto be supplied from theblower 30 through the pipe 36 and delivered therefrom he air agitatesthe chemicals added to the oil and prevents them from settling. rlheheater 15 is then started and the oil is heated and air is continuallyblown there-v through.

The heating of the oil and the blowing of air therethrough volatilizesthe water and lighter hydrocarbons such as gasoline which pass offthrough the vent pipe 22. The s0- i dium carbonate neutralizes any acidconstituents which may be present, and coagulates` the small particlesof carbon and other impurities, thereby facilitating filtering. Vhen thedesired temperature of the mixture of oil and chemicals in the tank hasbeen reached, the thermostat 17 automatically shuts off the current tothe heating coil.15

and lights the signal light 1,8.` The tempera- G0, ture to which the oilis subjected depends upon what flash point oil it is desired to produce.lf it is desired to produce an. oil having a flashpoint of 400, the oilis heated to. a temperature of about 355 F'. Ordi- Gv-narily the heatingand blowing occupies ln the v from 2 to 21/2 hours before the desiredtemperature is reached,

`When the signal lamp 18 is lighted, the operator knows that thetreatment of oil in the tank 2 is complete. Diatomaceous earth andpurified oil are then pumped into the tank 2. The amount of earth usedis about 1 lb. for 10 gals. of oil being purified. About 1 gal. ofpurified oil is mixed with each pound of earth in order to form a fluidn'iixture which can be readily pumped into the tank. The earth andpurified Oil are introduced into the tank through the pipe 40, pump 31,and pipe 43. The mixture of oil, alkali, aud diatomaceous earth is the-npumped from the tank to the filter 49. During the passage of the oilfrom the tank to the filter, and during the entire filtering process,air is continually delivered from the blower 30 to the tank 2. Thethree-way valves 44 and 45 are operated so as to cause the oil which hasbeen treated in the tank 2 to flow hrough the pipe 50, ittino' 51, valve44` through the pump 31, valve 4o and. pipes 4G and 47 to the filter 49.After being filtered the oil passes through a pipe to a storage tank.

1n case the filter becomes clogged or for any other reason the pressurein the connections between the oil pump 31 and the filter 49 increasesbeyond a predetermined limit, the relief valve 57 in the pipe 55opensthereby causing the oil to be again delivered to the inlet of theoil pump 31, until such time as the excess pressure in the pipe 47 islowered and the relief valve 57 closes. When the relief valve 57 isclosed the oil from the pump 31 passes through the pipes 46 and 47 tothe lilter 49, from which it is delivered through the filter outlet 85to storage tanks.`

During treatment .of the oil in the tank 2, air is blown through the oilbefore it is heated. The sodium` carbonate is dissolved in water beforeit is mixed with the oil, and if the mixture were heated without havingair blown therethrough the mixture would froth. During the filteringoperation the air -is continually blown into the tank 2 in order toprevent the combustible vapors which ordinarily pass out of the ventpipe 22 from being` sucked into the tank 2 and exploding.

The blowing of air into the mixture of oil and chemicals in the tank 2lowers the temperature to which it is necessary to heat the oil in orderto produce an oil of a predetermined flash point. It tends to break upthe emulsion'of oil and water, and reduces the vapor pressure of themixture.

` rilhe air also scrubs the bottom of the tank and keeps the mixtureagitated so as to cause complete reaction of the chemicals withtheimpurities in the oil.

W'e have illustrated and described the present preferred formoffapparatus, and.`

have described in detail the preferred method of carrying out theprocess. It. is to be understood, however, that-the invention may beotherwise embodied or practiced within the, scope of the lfollowingclaims. y

We claim:. c* y' l. The process of treating used lubricating oilcontaining lighter hydrocarbons and c water, 'comprising heating iii atank to atemperature,sufficient .to vaporize the hight-v er hydrocarbonsand water7 a mixture` 'of oil, sodium carbonate 'dissolved in water, anddiatomaceous earth,v introducing Aad] acent the bottom Aof the tank andduring the y entire heating operation air under pressure to agitato themixture, and thereafter ilterair into the tank. v c

2. The process of treating used lubricabv ing oil containing lighterhydrocaibons and water, comprising mixing-with thevoil sodium carbonateand Vdiatoniaceousearth in ing the mixture `while continuing to blow theproportion of'about l lb. sodium car-A bonate and l lb. diatoinac'eousearth to 10 gals. of oil, heating theiniXture ina tank to a temperaturesuilicien't to Vaporize the lighter hydrocarbons and water, and blowingair therethrough` during the vcheating,vk

and thereafter vfiltering the mixture while continuing toblow'airinto'the tank.'

`3. The process of treating used lubricatino' .D oil 't containinglighter Y hydrocarbons and wateivycoinprising mixing with the oil sodi-Y uincarboiiate and diatomaceousearth in the proportion orf-about l 1b.sodium carbonate and-l lb. diatoinaceous earth` tol() gals. of

heating the mixture in a` tank to about l355" F. to'vaporize the lighterhydrocarbons and water aiidjblowing air therethrough I during theheating and thereafter filtering the mixture while continuing to blowair in"l to l0 gallons ot' oil, heating the mixture to f vabout 355 F;in a tank iii-order to Vaporize thelighter hydrocarbons v`and water andtank.

l WALTER G. HOFFllIAN.

JAMES R. 'MILLERl u .blowingair through mixture duringthe. heating, andthereafter filtering the ini'X-` ture While continuing to'blow airintothe` its

